168 Mr. G. W. Todd : Further Experiments on the 



The dotted line in the curves (fig. 2) shows the relation 

 between the product pu and the pressure p for carbon dioxide 

 when the plates of the alternating chamber were 5 cm. apart. 



n</ pifu( 







Jl. 



The difference between the dotted and continuous curves is 

 remarkable, and should lead to information concerning the 

 nature of the ions at low pressures. In a paper containing 

 results of experiments on the mobility of negative ions at 



